Interferon acts to mediate natural immunity to protect against viral infection and to initiate inflammatory reactions that protect against bacterial infections. Interferon has also been shown to be an effective anti-tumor or anticancer agent.
Previously, the administration of interferon has often required frequent subcutaneous injections, given at intervals which resulted in fluctuating medication levels. However, many conditions treated by interferon therapy may respond better to controlled levels of interferon which may provide more effective prophylactic or therapeutic effects.
Attempts to control and sustain medication levels in humans or animals between the administration of doses have more recently included the use of biodegradable polymers as matrices for controlling the release of medicaments. In some cases, biodegradable polymers, under in vivo conditions, exhibited high initial bursts of medicament release and minimal release thereafter.
Furthermore, methods used to form controlled release compositions have often resulted in a loss of activity of the medicament due to the instability of the medicament, chemical interactions between the medicament and the other components contained in, or used in formulating, the controlled release composition, or have resulted in losses of medicament due to the formulation process.
Therefore, a need exists for a means of controlling the release of interferon while not inordinately reducing the activity, or potency, of the interferon released.